---

2.1 Earths crust in motion

Vocabulary:

Earthquake- is the shaking and trembling that results from the movement of rock beneath earth's surface.

Stress- a force that acts on rock to change its shape or volume.

Shearing- Stress that pushes a mass of rock in two opposite directions.

Tension- force pulls on the crust, stretching rock so that becomes thinner in the middle.

Compression- the force that squeezes rock until it folds or breaks.

Deformation- any change in the volume or shape of earth's crust.

Fault- is a break in earth's crust where slabs of crust slip past each other.

Strike-slip-fault- the rock on either side of the fault slip past each other sideways with little up-or-down motion.

Normal fault-the fault is at an angle so one block of rock lies above the fault while the other block lies below the fault.

Reverse fault- has the same structure as a normal fault, but the blocks move in the opposite direction.

Fault- block mountain- forms when normal faults up lift a block of rock.

Folds- bends in rock that form when compression shortens and thickens part of earth's crust.

Anticline- a fold in rock that ends upward in to an arch.

Syncline- a fold in rock that bends downward in the middle to form a bowl.

plateau- is a large area of flat land elevated high above sea level.

Outline:

---

Stress in the Crust

• Crust is moving

Types of Stress

• Shearing
• Compression
• Tension

Kinds of Faults

• Normal Faults
• Reverse Faults
• Strike-Slip Faults

Mountain Building

• Mountains formed by Faulting
• Mountains formed by Folding
  • Anticlines and Synclines
  • Plateaus

Diagram

---

`